Friday, August 29, 2014

Windows of the Photography

Now this may sounds like we are talking about some operating system of a computer .... right !

Well not exactly .... i am here referring all those windows which we have in our home in every room, door ways & hall from which sunlight or any other kind of source of light get enter and we can use this light to capture stunning images/portraits.

So why windows? Why not door? ... why not any other structure available in home from which light can be passes ? ..... Well answer is .... we can use almost any structure inside out home from which light can be passes and get modified in flattering way ....

When i started photography i use to capture images of my kids at home .... At that time i didn't have any flash or any other light source. So i practiced a lot at home over my kids using window light as its almost available instantly with any effort and kids are familiar with it.

Later i found out that many great photographers also using the same "Window" Technique to get the flattering effect of light and get very stunning portraits. That's one of the another reason why windows light is used to so much for "Black and White" images because of its flattering and "Wrap around" kind of effect. I will show some examples shortly below what i mean by "wrap around" effect.

So how u starts using window light? .... you might be thinking you go near to the window and just start taking images !!!!! ..... well yes exactly thats how you kick off :) .... You take the model .... place it at the side of the window and start taking images.

Note that there are different types of light coming from window .... for example ..

1- Hard Direct Sunlight which comes straight into the room through windows which we often blocked using window curtain. Not a pleasing light at the first place. Most probably you need to diffuse it before you use. So how we can diffuse it? .... Simple .... Used any plain shower curtain and put it over the window to diffuse the light .... Or .... Use any white bedsheet to put it over the window and get diffuse light ..... or just simply pull off the window curtain to block/diffuse it (note that the diffusion of such light will heavily be depending on the type of your window curtain). The more layers of shower curtain/bedsheet you going to use .... the more light going to diffuse and get flattering effect. But yes, it does requires some extra effort before you use it.

2- Side Sunlight which usually harsh and direct during noon time but when sun goes to set it becomes softer due to sun position. So the best time to use such light is either 10 o'clock when Sun is not much high ..... or 4 o'clock when sun is going to set. You cannot use such light in the middle of the day. Well yes you can but you need to work on the window light to diffuse it as per above point.

3- Bounce Sunlight which usually get inside from window by getting bounce from any near by structure or building. Such light is already diffused and flattered and can be used directly.

Fortunately i am getting Type-3 light from above list at my home .... My bedroom windows is facing another big apartment building. So logically sunlight suppose to be block. But the direction of Sunset was at the "BACK" of my apartment so light fall straight at the building which is in front of my apartment .... gets  modified/flattered/diffused and then get inside my bedroom through the windows glass and curtain which further double diffuse the light to give me perfect soft, wrapping light. Below are the few examples which i shot at home.

So as you can see .... all images above images are taken using light coming from window .... nothing more.

So how harsh direct Sunlight is going to be? .... Take a look below for sample image. The harsh light is always edgy and not pleasing unless you not use it directly or digitally modified. Another point one need to learn that ... the far model is from the window ... the more harsh light is going to be ..... the more close you are from the window .... the more soft kind of effect you will get from the same harsh direct sunlight. Check below first 3 images where the models are far from the window so for them light was harsh ... direct and very edgy .... where as in the 04th image, the same direct sunlight was producing kind a soft wrapping light kind a effect even model is right next to the window wearing sun-glasses to avoid direct light.

In below image, the mode is close to the window thats why you can see soft wrapping of light kind a effect unlike above 3 images. All this happening due to "Inverse Square Law". 

In below image, i have deliberately positioned the model in a specific way so her face down get blown out due to harsh sun light .... I used direct sunlight as a source to illuminate model side way only ....

(This image is taken using Nokia 808 Pure View)

I have been told by one great photographer that .... the bigger the "Aperture" or opening of the window .... the more flattering and diffuse image is going to be. So i thought to give my self a try .... Below are the sample images. The first two images are taken inside the parking lot which got massive opening outside towards the sun.

The below image is result of big glass wall where the intensity of light is controlled by "Curtains" of the window which act exactly like "Aperture" of the camera. You can change the intensity of the light by opening or closing the curtains of the window.

Oh ..... i almost forget about the doors. What happens if we use door as an example. Lets take a look.

So above images clearly shows one thing .... the bigger the the door .. the more "wrap around" of light you will have.

Even you can use window light to capture Professional Portrait for Linkedin .....

To sum things up in the end .... i would like to stress on one thing .... As you can see ... almost all of the images you have seen so far in this blog are B&W images .... why is that ? .... reason is simple ... i have found window light the best source to get the flattering effect which i always need for B&W images .... such light gives me soft wrapping effect as i explained above by keeping the model close to the window and at the same time i can use high contrast in post processing to get the punchy feeling which is the core beauty of B&W images.

So if you have prime lens (say 35mm or 50mm f/1.8 lens) .... and a window at your home (for sure you will have it) ..... you can take unlimited stunning images inside your home at any point of time when sun is up in the sky. No need to go outside. There are many many world famous photographers out there who are using only and only window as a light source to take their model images.

So enjoy more B&W images which i capture using Window Light ..... or in short .... WINDOWS OF PHOTOGRAPHY and see their different effects as per SUN position ..... :)

Happy Learning Guys !!!

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Friday, July 11, 2014

Do we really need more Mega Pixels?

This is long pending blog which i have been requested few months back from one of a leading Photographer of Pakistan to let amateur photographer the need or no-need of "Mega Pixels" ...

Mega Pixel war is not new .... its bin here since the dawn of the digital photography era. There is a great deal of importance placed on the issue of megapixels in the world of digital photography to the point that it’s the first question you ask: “How many megapixels does your camera have?”  It’s even gotten to the point where “low” megapixel cameras are almost seen as inferior to “high” megapixel cameras. Is this actually the case?

Consumers have come to believe that the more megapixels the better the camera. Is this true? Let’s get the answer to this question out of the way right now: “NO!” A better question to ask is “Do I need a camera with loads of megapixels?” Well, that depends. Let me explain further.

Putting it simply, more megapixels does NOT mean a “better” camera or a give you “higher quality” photograph.  So, what’s the big deal about megapixels?

So, What Are These “Megapixels” Anyway?

In every digital camera, the image is captured by a image sensor. In a digital SLR, when you click the shutter button, light travels through the lens and hits the image sensor at the back of the camera. The image sensor is made up of millions of “pixels”.  One megapixel equals “one million pixels”.  Think of pixels as microscopic “buckets” that capture light. These buckets or pixels are laid out on an image sensor in checkerboard fashion.
For example a typical digital SLR at the lower end of the price scale may have an image sensor with an array of 3,888 pixels by 2,592 pixels. Doing the math, 3,888 x 2,592 = 10,077,696 pixels, which is approximately 10 megapixels.
At the other end of the spectrum, a top-of-the-line digital SLR might have an image sensor with an array of 5,616 pixels by 3,744 pixels. Again, doing the math, this works out to 21,026,304 pixels or approximately 21 megapixels (The famous 5D Mark II) .... or Like Nikon D800/D800E/D810 with whooping 7360 x 4912  pixels equal 36.15 Mega Pixels.

Putting it simply,
  • Megapixels represent how many pixels or buckets are available on the camera’s image sensor to catch the light coming into the camera when taking a picture.
  • The more megapixels, the higher the resolution of the photos, meaning the more “detail” in the photograph

More Megapixels Does Not Necessarily Mean “Better”

So which is better? The 10 megapixel camera or the 21 megapixel camera? Well, the answer is, it depends! Obviously, the more pixels a camera has, the more detail (or resolution) the image will have since there are more “buckets” of light that have been captured. But does this translate to “sharper” images? Not necessarily!

Let’s suppose I took a picture with a 4 megapixel camera and a 10 megapixel camera and then I print both pictures to the size 5 inches by 7 inches. Which picture will look sharper? The fact is that they will both look identical. You will not be able to tell the difference. At this size, it is too small for the number of pixels to make a difference to the naked eye

On the other hand, if I were to enlarge both pictures to 11 inches by 14 inches, the 10 megapixel photo would now begin to look noticeably sharper compared to the 4 megapixel photo which would look grainer or “noisier”. Why is that? Because the larger the printed image becomes, the more the individual pixels begin to show.  If there are more pixels to start with, for example with a 10 megapixel camera compared to a 4 megapixel camera, then the more you can enlarge the photo before each of the individual pixels begin to show. Take a look at the bottom image ....

How many megapixels do you really need?

It depends on how large a sharp print one wants to make. For sharp prints use the formula: print width x 300 x print length x 300. You can relax the quality by changing the 300 value to 240. Much below 240 and the perceived print quality drops rapidly. Megapixel needs are shown in the table:

Number of megapixels for given print quality
Print size
300 pixels/inch240 pixels/inch
4 x 62.21.4
5 x 73.22.0
8 x107.24.6
11 x1413.98.9
16 x2028.818.4

Sensor Size and Picture Quality

The size of a camera's image sensor is the main determinant of picture quality and the larger the sensor area, the higher the potential for producing top-quality digital pictures. Equally important is the size of the actual photosites (buckets as mentioned above) on the sensor that collect the image-making light. The larger the photosites, the more light they can collect and, consequently, the more image data they make available to the camera's image processor. (Details of how to calculate the size of sensor photosites are provided below.

Sensor "Type"Imaging Area dimensions (width x height x diameter in mm)
1/2.7-inch (mobile)5.37 x 4.04 x 6.72
1/2.5-inch (mobile)5.76 x 4.29 x 7.18
1/1.8-inch 7.18 x 5.32 x 8.93
1/1.7-inch 7.6 x 5.7 x 9.5
2/3-inch8.8 x 6.6 x 11.07
Four Thirds (Point and Shoot) 18.0 x 13.5 x 22.5
APS-C (Canon )22.2 x 14.8 x 26.7
APS-C (Nikon)23.7 x 15.7 x 28.4
APS-C (Sony)23.6 x 15.8 x 28.4
(Canon professional DSLR)28.1 x 18.7 x 33.8
Full Frame (=35mm frame)36 x 24 x 44.3

Advantages of having Lower Mega Pixels for better ISO

Now this is noticeable thing .... Why DSLR with much higher ISO range have less mega pixels? Here is the list of the high-end camera with the fewer & higher mega pixels ... along with their highest available ISO ranges. Check it out.

If you notice, the lower the resolution, the better the ISO performance. Why is that??? 

Here is the deal ... what happens is, In above list all cameras are full frame. So it means the sensor size in all cameras are 36mm x 24mm. So what happening is regardless of how many MP are there, they are ending up fitting in into the same 36mm x 24mm sensor. Its like you are trying to push 12, 16, 18, 21, 22 or 36 people into 36 x 24 feet room. The more the people into the room the less the space they will going to get into the room which in this case is calls "Pixel Pitch". 

If you look at the last line which is pixel pitch which is the "width/space" of the photosites (or buckets or simply calls PIXELS) which captures the light. The more the width of the photosites, the better its capture light which means "LESS NOISE". Thats why few years back, many camera manufactures prefer to have less MP for better low light performance of the sensor. D700 is the perfect example of it. Regardless it got the 01st generation of EXPEED processor which was very slow when it comes to Noise Reduction, its pixel width was the biggest from above list which means its sensor was better in capturing low light with less noise in compared to all in the above list. I personally shot D700 at 8000 ISO and still it was less noise even though it got old processor. Imagine if it gets new EXPEED 4 processor. It will blow everything away. Nikon Df is one of the perfect example of it. Though its not a direct replacement of D700 but its more or like it. With no video feature just like D700, and less mega pixels ... in addition to it new EXPEED 3 processor, its ISO capability range shoots upto 204800 ISO makes it equals to D4 which is a Pro Body.  

In opposite to that, logically speaking if we have more mega pixels which will leads to smaller pixel width which means higher noise into the image. How is that possible? more pixel leads to noise !!!!!! 

Imagine, there is a room of 36x24 feet. Instead of 12 people i pushed 36 people into it. What will happen? well at first people will have less space (less pixel width) and if i give them task to do (capturing light in this case) there will be more noise and chaos in the room in compared of if i request the same task to 12 people which leads to the less noise and less Chaotic. D800 is the perfect example of it. But Nikon new EXPEED 3 processor was designed to combat this situation of higher noise and able to control the ISO upto 25,600 but not more. Canon on other hand played wisely and able to balance the higher resolution vs noise factor in their new camera body line up. I personally believe thats one of the reason Canon is not offering anything beyond 22.3 mega pixels because of the higher noise induction factor due to more mega pixels cramping into small space. 

In todays hi-tech world, technology evolved and new micro processor  played a vital role in digital imagining with incredible noise reduction performance. EXPEED 4 from Nikon & DIGIC 5+ from Canon are the leading examples. 

Enough with the pixels vs noise, switching back to the reality. Do we really need higher mega pixels? 

Well if you ask me, 12MP is more then enough. To print standard A4 paper in reality we need only 8MP. You need higher resolution for printing billboards. So dont get into this marketing stuff that higher resolution leads to better image quality. Yes you will get better resolution which you can use to crop the images which often need but not the better image. If you take crappy pictures with 36MP cameras, still it is going to be crappy image :) . 

And practically speaking when the last time you print your image? We always upload our images over the social media where it end up in compressed and less quality format regardless of any higher resolution camera we used .... that includes your 8MP iPhone :) 

So this is to address the question ..... do we really need more mega pixels ..... practical answer .... NO!

Happy learning guys !

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Sunday, June 1, 2014

What is GN ?????

So what the hell is that GN thing ...???  .... Any wild guess ???

Ok lets start from the scratch .... 

GN term is basically belongs to the world of FLASH PHOTOGRAPHY. A world which is not liked by many (lets be honest here) .... Don't like not because of the hardware it self or price .... people hate it because they not able to control the flash at the beginning and thats where the turning point it. At the beginning when you see trouble .... exactly at that point either you make it or break it :) .

So i was telling the GN thing here .... Let me get in my comfort zone by copy pasting the definition from the WIKIPEDIA :) 

"The guide number (GN) for an electronic flash measures its ability to illuminate the subject to be photographed at a specific film or sensor sensitivity and angle of view. A higher guide number indicates a more powerful flash."

The guide number is the product of the maximum flash-to-subject distance and the f-number of the aperture that will correctly expose film or a digital sensor with the specified sensitivity."

GN = distance × f-number

Even it took me some time to get what Wikipedia is saying here .... Lets get practical now gentlemen.

So what is Guide Number?

In simple mathematical terms, it is the aperture multiplied by distance, in which your flash can PROPERLY EXPOSE a subject at a given distance (aperture and distance). The standard GUIDE NUMBERS you should be looking for are measured at ISO 100 (film speed), at 35mm flash head position, at full 1/1 power. 

Lets take a basic Nikon Flash (yes i am proud Nikonian) for an example. The SB700 has a GN of 92. To make our math easier, we'll around it off to 100. Lets take a look at our diagram to see what this means. We have a flash and a subject.They are 20 feet away in distance.

To properly expose our subject, we would need an aperture of f/5 ... Why? 

Because .... f/5 x 20' = 100GN

Now what happens if we move our subject 20' further away ...... !!!!

To compensate for this additional distance, we would need to let in more light! This means we will have to open up our camera aperture to f/2.5 

f/2.5 x 40' = 100GN

If we kept our aperture at f/5, we would underexpose our subject. Likewise, if we opened up our aperture too much ..... say for example f/1.4 .... we would overexpose our Subject. Got it?

Note that all of the above calculation are done based on the assumption of ISO100 (already highlighted in blue above). So what if we have ISO more then 100 ????

Converting Guide Number for ISO
The Guide Number charts are typically always printed showing ISO 100 values, but we can just multiply ISO 100 GN values by 1.41 to get ISO 200 GN values, or multiply by 2 to get ISO 400 GN values, etc. Or we can divide if converting going the other way.

Note that all values in the "Factor" line is the hundredth of the Square root of the ISO.

Doubling Guide Number doubles distance range, or doubles f/stop number, which is two more stops.
Doubling flash zoom number should theoretically multiply Guide Number by 1.414, but only as an approximation, because of course, it depends on the individual reflector design.

Lets have some example here ..... Suppose we plan to use direct flash at f/8 at 12 feet at ISO 400.

So we know we need flash power of f8 x 12 feet = GN 96 (feet) at ISO 400. The charts are always for ISO 100 that comes with the flash manual for any flash. Below is the GN chart of SB800 as an example here  where distance of the flash with subject is given in meters/feet.

We know the ISO 400 factor is x2 (from above converting guide factor). So now we need to scale down ISO 400 to ISO 100 to check the flash power from the above chart and that we can do by dividing ISO400 by 2.
Converting this to ISO 100 is GN 96/2 = GN 48 (feet, ISO 100). We search the guide number chart in the speedlight manual (ISO 100), and maybe we find this value at 24mm zoom and 1/4 flash power to be say GN 49 feet. More than close enough to 48. This SB-800 GN chart below (for an example) says that 24mm flash head zoom and 1/4 flash power is GN 49, almost exactly the GN 48 that we need.
The charts show GN as both meter and feet values (as meters/feet), so use either one, so long as you are consistent with units. Duplicate this situation by setting flash to 24mm zoom, 1/4 power, and set the camera at ISO 400 and f/8, and you're very close on first try for a 12 foot flash distance (direct flash). Or, the chart includes several other combinations of power level and zoom which are near GN 49. It need not be exact, GN varies with f/stop numbers so that another GN value of about 12% difference is roughly within 1/3 stop (and 41% is one stop). We don't necessarily have to match flash zoom to lens zoom values, we can use any wider flash zoom - which may waste a little light if the flash is wider than the lens, which is no problem if not at maximum power (some flashes do not zoom anyway). FX flash on DX cameras is already 1.5x wider anyway. To adjust results of this method, you can simply adjust the power level by 1/3 stop, or adjust the aperture by 1/3 stop. Or zooming the flash head makes steps sometimes roughly about 1/3 stop (no bets, there is no actual relationship). 

I hope we all use this GN thing at some point in our flash photography .... practically speaking.

Happy learning Guys :)

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